WO2012118343A2 - Method and apparatus for transmitting a sounding reference signal by a terminal - Google Patents

Method and apparatus for transmitting a sounding reference signal by a terminal Download PDF

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WO2012118343A2
WO2012118343A2 PCT/KR2012/001573 KR2012001573W WO2012118343A2 WO 2012118343 A2 WO2012118343 A2 WO 2012118343A2 KR 2012001573 W KR2012001573 W KR 2012001573W WO 2012118343 A2 WO2012118343 A2 WO 2012118343A2
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component carrier
carrier
reference signal
sounding reference
terminal
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PCT/KR2012/001573
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French (fr)
Korean (ko)
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WO2012118343A3 (en
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서동연
김민규
양석철
안준기
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엘지전자 주식회사
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0053Allocation of signaling, i.e. of overhead other than pilot signals
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/0001Arrangements for dividing the transmission path
    • H04L5/0003Two-dimensional division
    • H04L5/0005Time-frequency
    • H04L5/0007Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
    • H04L5/001Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT the frequencies being arranged in component carriers
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0032Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
    • H04L5/0035Resource allocation in a cooperative multipoint environment
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048Allocation of pilot signals, i.e. of signals known to the receiver
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00Arrangements affording multiple use of the transmission path
    • H04L5/003Arrangements for allocating sub-channels of the transmission path
    • H04L5/0078Timing of allocation
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation
    • H04W72/044Wireless resource allocation where an allocation plan is defined based on the type of the allocated resource
    • H04W72/0453Wireless resource allocation where an allocation plan is defined based on the type of the allocated resource the resource being a frequency, carrier or frequency band
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B7/00Radio transmission systems, i.e. using radiation field
    • H04B7/02Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0667Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal
    • H04B7/0671Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of delayed versions of same signal using different delays between antennas
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04LTRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00Baseband systems
    • H04L25/02Details ; Arrangements for supplying electrical power along data transmission lines
    • H04L25/0202Channel estimation
    • H04L25/0224Channel estimation using sounding signals
    • H04L25/0226Channel estimation using sounding signals sounding signals per se
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04WWIRELESS COMMUNICATION NETWORKS
    • H04W72/00Local resource management, e.g. wireless traffic scheduling or selection or allocation of wireless resources
    • H04W72/04Wireless resource allocation
    • H04W72/0406Wireless resource allocation involving control information exchange between nodes
    • H04W72/0413Wireless resource allocation involving control information exchange between nodes in uplink direction of a wireless link, i.e. towards network

Abstract

Provided is a method for transmitting a sounding reference signal by a terminal, and a terminal using the method. The method comprises the following steps: receiving carrier information indicating the carrier via which a sounding reference signal is to be transmitted; receiving a physical downlink shared channel (PDSCH) through a first downlink component carrier; and transmitting a sounding reference signal through a second downlink component carrier, wherein the second downlink component carrier is determined based on the carrier information.

Description

Method and apparatus for transmitting a sounding reference signal of a terminal

The present invention relates to wireless communication, and more particularly, to a method and apparatus for transmitting a sounding reference signal by a terminal.

The International Telecommunication Union Radio communication sector (ITU-R) is working on the standardization of International Mobile Telecommunication (IMT) -Advanced, the next generation of mobile communication systems after the third generation. IMT-Advanced aims to support Internet Protocol (IP) -based multimedia services at data rates of 1 Gbps in stationary and slow motions and 100 Mbps in high speeds.

3rd Generation Partnership Project (3GPP) is a system standard that meets the requirements of IMT-Advanced. Long Term Evolution is based on Orthogonal Frequency Division Multiple Access (OFDMA) / Single Carrier-Frequency Division Multiple Access (SC-FDMA) transmission. LTE-Advanced (LTE-A) is being prepared. LTE-A is one of the potential candidates for IMT-Advanced.

As technologies that can be applied to next-generation communication technologies such as LTE-A, there are carrier aggregation (CA) and cooperative multi-point transmission. Carrier aggregation is a technique of providing a wideband by aggregating a plurality of carriers having a narrow band. Cooperative transmission is a technique of increasing system performance and efficiency by transmitting a signal to a plurality of transmitting end in cooperation with the same receiving end.

On the other hand, the terminal transmits a reference signal to measure the uplink channel state. Among these reference signals, a reference signal that is not related to uplink data or uplink control information transmitted by the terminal is called a sounding reference signal (SRS). The sounding reference signal is transmitted 1) periodically or aperiodically 2) after receiving the triggering signal.

Conventionally, a carrier used for aperiodic transmission of a sounding reference signal has been defined as a downlink carrier receiving a data channel and an uplink carrier linked by system information. However, in case of carrier aggregation, the UE may receive a data channel through a downlink carrier without a linked uplink carrier. Alternatively, even in the case of cooperative transmission, even when a data channel is received through a downlink carrier having a linked uplink carrier, uplink transmission through the linked uplink carrier is not configured at the time of transmitting a sounding reference signal. May occur.

Accordingly, there is a need for a method and apparatus for transmitting a sounding reference signal of a terminal that can be performed even in the above-described case.

A method and apparatus for transmitting a sounding reference signal of a terminal are provided.

In one aspect, a method of transmitting a sounding reference signal of a terminal is provided. The method includes receiving carrier information indicating a carrier to transmit a sounding reference signal; Receiving a physical downlink shared channel (PDSCH) on a first downlink component carrier; And transmitting a sounding reference signal through a second uplink component carrier, wherein the second uplink component carrier is determined based on the carrier information.

The first downlink component carrier may be a downlink component carrier having no uplink component carrier linked by system information.

The first downlink component carrier is a downlink component carrier linked with a first uplink component carrier according to system information, and the first uplink component carrier is an uplink transmission in a subframe that transmits the sounding reference signal. It may not be set.

The method further includes receiving a physical downlink control channel (PDCCH) for scheduling the PDSCH from a serving base station, wherein the PDSCH is received from a cooperating base station cooperatively transmitting with the serving base station and the sounding reference signal is received. It can transmit to the serving base station.

The PDCCH may include a signal that triggers the sounding reference signal transmission.


The carrier information may be received through a radio resource control (RRC) signal.

In another aspect, a method of transmitting a sounding reference signal of a terminal is provided. The method includes receiving a physical downlink shared channel (PDSCH) on a first downlink component carrier; And transmitting a sounding reference signal through a second uplink component carrier, wherein the second uplink component carrier is a predetermined uplink component carrier.

The second uplink component carrier may be an uplink component carrier file included in a primary cell where the terminal performs an initial connection establishment procedure or a connection reestablishment procedure with a base station.

In another aspect, a terminal is provided. The terminal includes an RF unit for transmitting and receiving a radio signal; And a processor coupled to the RF unit, the processor receiving carrier information indicating a carrier to transmit a sounding reference signal, receiving a physical downlink shared channel (PDSCH) through a first downlink component carrier, And transmitting a sounding reference signal through a second uplink component carrier, wherein the second uplink component carrier is determined based on the carrier information.

The first downlink component carrier may be a downlink component carrier having no uplink component carrier linked by system information.

The first downlink component carrier is a downlink component carrier linked with a first uplink component carrier according to system information, and the first uplink component carrier is an uplink transmission in a subframe that transmits the sounding reference signal. It may not be set.

The processor further receives a physical downlink control channel (PDCCH) for scheduling the PDSCH from a serving base station, wherein the PDSCH is received from a cooperating base station cooperatively transmitting with the serving base station, and the sounding reference signal is transmitted to the serving base station. Can be.

The PDCCH may include a signal that triggers the sounding reference signal transmission.

The carrier information may be received through a radio resource control (RRC) signal.


According to the prior art, even if the terminal cannot transmit the sounding reference signal, the present invention may transmit the sounding reference signal. A terminal receiving a signal by carrier aggregation or cooperative transmission may smoothly transmit an aperiodic sounding reference signal. Thus, uplink channel measurement and scheduling performance of the system is increased.

1 shows a radio frame structure of 3GPP LTE.

2 is an exemplary diagram illustrating a resource grid for one downlink slot.

3 shows a structure of a downlink subframe.

4 shows a structure of an uplink subframe.

5 shows an example of a subframe in which a sounding reference signal is transmitted.

FIG. 6 illustrates SRS transmission of a terminal when transmitting an SRS triggering signal through a PDCCH including a DL grant.

7 illustrates SRS transmission of a terminal when transmitting an SRS triggering signal through a PDCCH including an UL grant.

8 is a comparative example of a conventional single carrier system and a multi-carrier system.

9 illustrates asymmetric aggregation with three serving cells configured for the UE.

FIG. 10 illustrates an example of an SRS triggering method in the situation of FIG. 9.

FIG. 11 illustrates a case where SRS transmission is a problem in the situation of FIG. 9.

12 shows a CoMP system to which the present invention can be applied.

13 shows an SRS transmission method of a terminal according to an embodiment of the present invention.

14 shows an SRS transmission method of a terminal according to another embodiment of the present invention.

15 is a block diagram illustrating a base station and a terminal.

The following techniques include code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA), orthogonal frequency division multiple access (OFDMA), single carrier frequency division multiple access (SC-FDMA), and the like. It can be used in various wireless communication systems. CDMA may be implemented with a radio technology such as Universal Terrestrial Radio Access (UTRA) or CDMA2000. TDMA may be implemented with wireless technologies such as Global System for Mobile communications (GSM) / General Packet Radio Service (GPRS) / Enhanced Data Rates for GSM Evolution (EDGE). OFDMA may be implemented in a wireless technology such as IEEE 802.11 (Wi-Fi), IEEE 802.16e (WiMAX), IEEE 802-20, Evolved UTRA (E-UTRA), and the like. UTRA is part of the Universal Mobile Telecommunications System (UMTS). 3rd Generation Partnership Project (3GPP) long term evolution (LTE) is part of an Evolved UMTS (E-UMTS) using E-UTRA, and employs OFDMA in downlink and SC-FDMA in uplink. LTE-Advanced (LTE-A) is the evolution of 3GPP LTE. In the following description, for clarity, 3GPP LTE / LTE-A will be described as an example, but the technical spirit of the present invention is not limited thereto.

A base station (BS) is a device that provides communication services for a specific geographic area. A base station generally refers to a fixed station communicating with a terminal, and may be referred to as other terms such as an evolved NodeB (eNB), a base transceiver system (BTS), an access point, an access network (AN), and the like. .

Terminal (User Equipment, UE) can be fixed or mobile, MS (Mobile Station), UT (User Terminal), SS (Subscriber Station), Wireless Device (Personal Digital Assistant), PDA (Wireless Modem) (Wireless Modem), handheld device (AT), AT (Access Terminal) may be called in other terms.

Hereinafter, downlink (DL) means communication from the base station to the terminal, and uplink (UL) means communication from the terminal to the base station.

A wireless communication system including a base station and a terminal is a system supporting bidirectional communication. Bidirectional communication may be performed using a time division duplex (TDD) mode, a frequency division duplex (FDD) mode, or the like. TDD mode uses different time resources in uplink transmission and downlink transmission. The FDD mode uses different frequency resources in uplink transmission and downlink transmission.

1 shows a radio frame structure of 3GPP LTE.

Referring to FIG. 1, a radio frame consists of 10 subframes, and one subframe consists of two slots. For example, one subframe may have a length of 1 ms, and one slot may have a length of 0.5 ms. The time taken for one subframe to be transmitted is called a transmission time interval (TTI). TTI may be a minimum unit of scheduling. The structure of the radio frame is only an example, and the number of subframes included in the radio frame and the number of slots included in the subframe may be variously changed.

2 is an exemplary diagram illustrating a resource grid for one downlink slot.

One slot in a radio frame includes a plurality of orthogonal frequency division multiplexing (OFDM) symbols in the time domain. The OFDM symbol is used to represent one symbol period since 3GPP LTE uses OFDMA in downlink, and may be called a different name according to a multiple access scheme. For example, when SC-FDMA is used, it may be referred to as an SC-FDMA symbol. One slot includes 7 OFDM symbols as an example, but the number of OFDM symbols included in one slot may vary according to the length of a cyclic prefix (CP). According to 3GPP TS 36.211 V8.5.0 (2008-12), one subframe includes 7 OFDM symbols in a normal CP and one subframe includes 6 OFDM symbols in an extended CP.

In addition, one slot includes a plurality of resource blocks (RBs) in the frequency domain. The resource block includes a plurality of consecutive subcarriers in one slot in resource allocation units. The subcarriers in the RB may have an interval of, for example, 15 KHz.

Each element on the resource grid is called a resource element (RE), and one resource block includes 12 × 7 resource elements. The number N DL of resource blocks included in the downlink slot depends on the downlink transmission bandwidth set in the cell. The resource grid described in FIG. 2 may also be applied to uplink.

3 shows a structure of a downlink subframe.

Referring to FIG. 3, a subframe includes two consecutive slots. The maximum 3 OFDM symbols of the first slot in the subframe are the control region to which control channels are allocated, and the remaining OFDM symbols are the data region to which the data channel is allocated. to be. The control region may consist of up to 4 OFDM symbols according to the system band.

Control channels allocated to the control region include a physical control format indication channel (PCFICH), a physical hybrid-ARQ indicator channel (PHICH), and a physical downlink control channel (PDCCH). The PCFICH is a control channel through which information indicating the size of the control region, that is, the number of OFDM symbols constituting the control region is transmitted. The PHICH is a control channel that carries ACK / NACK (acknowledgement / not-acknowledgement) for uplink data transmission of the UE. The PDCCH includes resource allocation of downlink-shared channel (DL-SCH) (also referred to as downlink grant) and transmission format, resource allocation information of uplink shared channel (UL-SCH) (also referred to as uplink grant). Paging information on paging channel (PCH), system information on DL-SCH, resource allocation of higher layer control messages such as random access response transmitted on PDSCH, transmission power control for individual UEs in any UE group and a set of transmission power control (TPC) commands and activation of Voice over Internet Protocol (VoIP). Control information transmitted through the PDCCH is called downlink control information (DCI).

The DCI format includes a format 0 for scheduling a physical uplink shared channel (PUSCH), a format 1 for scheduling one physical downlink shared channel (PDSCH) codeword, and a format 1A for compact scheduling of one PDSCH codeword. Format 1B for simple scheduling of rank-1 transmission of a single codeword in spatial multiplexing mode, format 1C for very simple scheduling of downlink shared channel (DL-SCH), format for PDSCH scheduling in multi-user spatial multiplexing mode 1D, format 2 for PDSCH scheduling in closed-loop spatial multiplexing mode, format 2A for PDSCH scheduling in open-loop spatial multiplexing mode, TPC of 2-bit power regulation for PUCCH and PUSCH Transmission power control) format 3, and format 3A for transmission of 1-bit power control TPC commands for PUCCH and PUSCH.

4 shows a structure of an uplink subframe.

Referring to FIG. 4, the uplink subframe is allocated a control region in which a physical uplink control channel (PUCCH) carrying uplink control information is allocated in a frequency domain and a physical uplink shared channel (PUSCH) carrying user data. It can be divided into data areas.

PUCCH for one UE is allocated to a resource block (RB) pair in a subframe, and RBs belonging to the RB pair occupy different subcarriers in each of two slots. This is said that the RB pair allocated to the PUCCH is frequency hopping at the slot boundary.

A sounding reference signal (SRS) will now be described.

SRS refers to a reference signal used for measuring channel quality in uplink. The SRS performs a function of enabling the base station to perform frequency selective scheduling by measuring channel quality for uplink. That is, the SRS is a reference signal that is not associated with uplink data transmission or control information transmission of the terminal.

However, the SRS may be used for other purposes, for example, initial modulation and coding scheme (MCS) selection, initial power control, etc., for a terminal not recently scheduled.

(1) Subframe setting in which the SRS is transmitted and the location in which the SRS is transmitted.

The subframe in which the SRS is transmitted by any terminal in the cell is indicated by cell specific broadcast signaling. For example, the 'srsSubframeConfiguration' parameter, which is a 4-bit cell specific signal, indicates 15 subframe sets in which an SRS can be transmitted in each radio frame. This flexible setup possibility gives you the flexibility to adjust the SRS overhead according to your deployment scenario.

On the other hand, the SRS is always transmitted in the last SC-FDMA symbol of the configured subframes. PUSCH is not transmitted in the SC-FDMA symbol designated as SRS is transmitted.

5 shows an example of a subframe in which a sounding reference signal is transmitted.

Referring to FIG. 5, the sounding reference signal is transmitted through one SC-FDMA symbol in a subframe. The SC-FDMA symbol in the period in which the sounding reference signal is transmitted will be referred to as a sounding symbol. Here, the last SC-FDMA symbol of the 14 SC-FDMA symbols constituting the subframe is a sounding symbol, but this is only an example, and the position or number of sounding symbols in the subframe may be changed in various ways.

The sounding reference signal is not transmitted in the control area but in the data area. The terminal may transmit the sounding reference signal over the entire frequency (or subcarrier) of the data region or over some frequency of the data region. When the UE transmits the sounding reference signal over some frequencies, the UE may hop and transmit a different frequency for each subframe in which the sounding reference signal is transmitted. In addition, the terminal may transmit the sounding reference signal using only subcarriers with even or odd indexes.


(2) Interval and Period of SRS Transmission

The base station may be configured to periodically transmit the SRS until 1) request the individual SRS transmission or 2) stop. For this purpose, a 1 bit terminal specific parameter, 'duration' is used, which indicates whether the requested SRS transmission is one-time or periodic. If periodic SRS transmission is configured for the UE, the period may be any one of 2, 5, 10, 20, 40, 80, 160, or 320 ms.

The period in which the terminal should transmit the SRS and the subframe offset value within the period are indicated by a 10-bit terminal specific parameter (referred to as 'srsConfigurationIndex').

(3) SRS band.

To support many SRSs, up to four SRS bands are supported simultaneously in LTE depending on the system band. In order to provide flexible settings for the SRS band values, eight sets are defined for each of the four SRS bands. The base station provides a 3-bit cell specific parameter called 'srsBandwidthConfiguration' through RRC signaling, which indicates one of the eight sets.

The following table shows eight sets for each of the four SRS bands when the uplink system band has a 80 to 110 resource block range.

TABLE 1

Figure PCTKR2012001573-appb-I000001

Which of the four SRS bands is used is set by a 2-bit terminal specific parameter (referred to as 'srsBandwidth'). As shown in Table 1 above, the smallest supported SRS band is 4 resource blocks. Such a small SRS band is used to provide higher quality channel information to a terminal with limited power.

Then, the SRS bands are set to be a multiple of each other. This is to provide frequency hopping between different SRS bands. Frequency hopping is enabled or disabled according to the value of the parameter 'frequencyDomainPosition' provided to each terminal.

The following table summarizes SRS configuration parameters (SRS parameter) signaled to the UE.

TABLE 2

Figure PCTKR2012001573-appb-I000002

In the above table, 'srsBandwidthConfiguration' indicates the maximum bandwidth in which the SRS can be transmitted in the cell.

'SrsSubframeConfiguration' indicates a possible set of subframes in which an SRS can be transmitted in each radio frame. 'SrsSubframeConfiguration' is a cell-specific broadcast signal transmitted to a terminal in a cell, and may be configured of, for example, 4 bits. The SRS may be sent in the last SC-FDMA symbol within the subframes in which the SRS may be sent. In the SC-FDMA symbol in which the SRS is transmitted, uplink data transmission of the terminal may not be allowed.

'SrsBandwidth' represents the SRS transmission band of the terminal. The SRS transmission band may be determined according to the transmission power of the terminal, the number of terminals that the base station can support, and the like. 'Duration' is a parameter indicating whether the base station requests one terminal SRS transmission or periodically transmits the SRS. By this parameter, the terminal may transmit the SRS only once or periodically transmit the SRS to the base station.

'TransmissionComb' indicates to which subcarrier the SRS transmitted by the UE is allocated. In order to support frequency selective scheduling in a multi-user environment, it is necessary to allow SRSs transmitted from different terminals and overlapping SRSs having different SRS bands. To support this, an interleaved FDMA (IFDMA) having a RePetition Factor (RPF) of 2 is used for an SC-FDMA symbol in which an SRS is transmitted. For example, this may indicate whether the SRS is transmitted on the odd subcarrier or the SRS on the even subcarrier in the SRS transmission band. In the time domain, RPF acts as a decimation factor in the frequency domain. When the SRS is repeated twice in the time domain in the SC-FDMA symbol in which the SRS is transmitted, the subcarrier on which the SRS is transmitted has a comb-like spectrum. In other words, the subcarrier on which the SRS is transmitted is composed of only even subcarriers (or odd subcarriers) in the allocated sounding band. Due to the IFDMA structure of the symbol on which the SRS is transmitted, the UE is assigned a parameter called 'transmissionComb'. ‘TransmissionComb’ has a value of 0 or 1 and indicates where the SRS is sent.

On the other hand, SRS may be transmitted aperiodic (aperiodic) at the request of the base station. Such aperiodic SRS transmission means that the terminal transmits the SRS when the base station dynamically transmits a triggering signal through the PDCCH.

FIG. 6 illustrates SRS transmission of a terminal when transmitting an SRS triggering signal through a PDCCH including a DL grant.

Referring to FIG. 6, DCI format 1A may be transmitted through a PDCCH of subframe N. FIG. DCI format 1A is used for compact scheduling or random access of one PDSCH codeword. The following information is transmitted in DCI format 1A. 1) flag to distinguish DCI format 0 and DCI format 1A, 2) localized / decentralized virtual RB designation flag, 3) resource block designation, 4) modulation and coding scheme, 5) HARQ Process number, 6) new data indicator, 7) redundancy version, 8) transmission power control (TPC) command for PUCCH, 9) downlink assignment index (TDD only), 10) SRS request (0 or 1) Bit). That is, the SRS request may be included in the DCI format for scheduling the PDSCH. Then, the UE can transmit the SRS in subframe M. Subframe M is an example of a subframe capable of transmitting SRS.

7 illustrates SRS transmission of a terminal when transmitting an SRS triggering signal through a PDCCH including an UL grant.

Referring to FIG. 7, DCI format 0 may be transmitted through a PDCCH of subframe N. FIG. DCI format 0 is used for PUSCH scheduling. Information (field) transmitted through DCI format 0 is as follows. 1) A flag for distinguishing DCI format 0 from DCI format 1A (0 indicates DCI format 0 and 1 indicates DCI format 1A), 2) hopping flag (1 bit), 3) resource block designation and hopping resources 4) modulation and coding scheme and redundancy version (5 bits), 5) new data indicator (1 bit), 6) TPC command (2 bits) for the scheduled PUSCH, 7) DM-RS Cyclic shift (3 bits), 8) UL index, 9) downlink designation index (TDD only), 10) CQI request, 11) SRS request (0 or 1 bit). That is, the 1-bit SRS request may be included in the DCI format for scheduling the PUSCH. Then, the UE can transmit the SRS in subframe K. Subframe K is an example of a subframe capable of transmitting SRS.

Meanwhile, a next generation communication system such as 3GPP LTE-A may be a multi-carrier system supporting carrier aggregation. The multi-carrier system refers to a system in which one or more carriers having a smaller bandwidth than a target broadband constitutes a broadband when the wireless communication system attempts to support the broadband. The multi-carrier system may be called other names such as a carrier aggregation system and a bandwidth aggregation system.

8 is a comparative example of a conventional single carrier system and a multi-carrier system.

Referring to FIG. 8, in a single carrier system, only one carrier is supported to the UE in uplink and downlink. The bandwidth of the carrier may vary, but only one carrier is allocated to the terminal. On the other hand, in a multi-carrier system, a plurality of component carriers (DL CC A to C, UL CC A to C) may be allocated to the terminal. For example, three 20 MHz component carriers may be allocated to allocate a 60 MHz bandwidth to the terminal.

The multi-carrier system may be divided into a continuous carrier aggregation system in which each carrier is aggregated and a non-contiguous carrier aggregation system in which each carrier is separated from each other. Hereinafter, simply referred to as a multi-carrier system, it should be understood to include both the case where the component carrier is continuous and the case of discontinuous.

When collecting one or more component carriers, the target component carrier may use the bandwidth used by the existing system as it is for backward compatibility with the existing system. For example, the 3GPP LTE system supports bandwidths of 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz, and the 3GPP LTE-A system may configure a bandwidth of 20 MHz or more using only the bandwidth of the 3GPP LTE system. Alternatively, broadband can be configured by defining new bandwidth without using the bandwidth of the existing system.

The system frequency band of a wireless communication system is divided into a plurality of carrier frequencies. Here, the carrier frequency means a center frequency of a cell. Hereinafter, a cell may mean a downlink frequency resource (ie, a downlink component carrier) and an uplink frequency resource (ie, an uplink component carrier). Alternatively, the cell may mean a combination of a downlink frequency resource and an optional uplink frequency resource. In addition, in general, when a carrier aggregation (CA) is not taken into consideration, an uplink component carrier and a downlink component carrier may always exist in pairs in one cell.

In order to transmit and receive packet data through a specific cell, the terminal must first complete configuration for a specific cell. In this case, the configuration refers to a state in which reception of system information necessary for data transmission and reception for a corresponding cell is completed. For example, the configuration may include an overall process of receiving common physical layer parameters required for data transmission and reception, or MAC layer parameters, or parameters required for a specific operation in the RRC layer. When the set cell receives only the information that the packet data can be transmitted, the cell can be immediately transmitted and received.

The cell in the configuration complete state may exist in an activation or deactivation state. Here, activation means that data is transmitted or received or is in a ready state. The UE may monitor or receive a control channel (PDCCH) and a data channel (PDSCH) of an activated cell in order to identify resources (which may be frequency, time, etc.) allocated thereto.

Deactivation means that transmission or reception of traffic data is impossible, and measurement or transmission of minimum information is possible. The terminal does not monitor or receive the control channel (PDCCH) and data channel (PDSCH) of the deactivated cell in order to check the resources (which may be frequency, time, etc.) allocated thereto.

The cell may be divided into a primary cell (PCell), a secondary cell (SCell), and a serving cell.

A primary cell (PCell) refers to a cell in which a terminal performs an initial connection establishment procedure or a connection reestablishment procedure with a base station, or a cell indicated as a primary cell in a handover process.

The secondary cell refers to a cell that provides additional radio resources that are established after the RRC connection is established.

The serving cell is configured as a primary cell when the carrier aggregation is not set or the terminal cannot provide carrier aggregation. When carrier aggregation is set, the term serving cell indicates a cell configured for the terminal and may be configured in plural. The plurality of serving cells may be configured as a set consisting of one or a plurality of cells among the primary cell and all secondary cells.

A primary component carrier (PCC) means a CC corresponding to a primary cell. The PCC is a CC in which the terminal initially makes a connection (connection or RRC connection) with the base station among several CCs. The PCC is a special CC that manages a connection (Connection or RRC Connection) for signaling regarding a plurality of CCs and manages UE context, which is connection information related to a terminal. In addition, the PCC is connected to the terminal and always exists in the active state in the RRC connected mode. The downlink component carrier corresponding to the primary cell is called a downlink primary component carrier (DL PCC), and the uplink component carrier corresponding to the primary cell is an uplink primary component carrier (UL PCC). Is called.

Secondary component carrier (SCC) refers to a CC corresponding to the secondary cell. That is, the SCC is a CC allocated to the terminal other than the PCC, and the SCC is an extended carrier for the additional resource allocation other than the PCC and may be divided into an activated or deactivated state. The downlink component carrier corresponding to the secondary cell is called a downlink secondary component carrier (DL SCC), and the uplink component carrier corresponding to the secondary cell is called an uplink secondary component carrier (UL SCC). Is called.

 The primary cell and the secondary cell have the following characteristics.

First, the primary cell is used for transmission of the PUCCH. Second, the primary cell is always activated, while the secondary cell is a carrier that is activated / deactivated according to specific conditions. Third, when the primary cell experiences a Radio Link Failure (RLF), RRC reconnection is triggered. Fourth, the primary cell may be changed by a security key change or a handover procedure accompanying a RACH (Random Access CHannel) procedure. Fifth, non-access stratum (NAS) information is received through the primary cell. Sixth, in the case of the FDD system, the primary cell is always configured with a pair of DL PCC and UL PCC. Seventh, a different CC may be configured as a primary cell for each UE. Eighth, the primary cell can be replaced only through a handover, cell selection / cell reselection process. In the addition of a new secondary cell, RRC signaling may be used to transmit system information of a dedicated secondary cell.

In the component carrier constituting the serving cell, the downlink component carrier may configure one serving cell, and the downlink component carrier and the uplink component carrier may be connected to configure one serving cell. However, the serving cell is not configured with only one uplink component carrier.

The activation / deactivation of the component carrier is equivalent to the concept of activation / deactivation of the serving cell. For example, assuming that serving cell 1 is configured of DL CC1, activation of serving cell 1 means activation of DL CC1. If the serving cell 2 assumes that DL CC2 and UL CC2 are connected and configured, activation of serving cell 2 means activation of DL CC2 and UL CC2. In this sense, each component carrier may correspond to a cell.

The multi-carrier system can support cross-carrier scheduling. Cross-carrier scheduling is a resource allocation of a PDSCH transmitted on another CC through a PDCCH transmitted on a specific CC and / or a PUSCH transmitted on a CC other than the CC which is basically linked with the specific CC. Scheduling method that allows resource allocation. That is, the PDCCH and the PDSCH may be transmitted through different downlink CCs, and the PUSCH may be transmitted through another uplink CC other than the uplink CC linked with the downlink CC through which the PDCCH including the UL grant is transmitted. . As such, in a system supporting cross-carrier scheduling, a carrier indicator indicating a DL CC / UL CC through which a PDSCH / PUSCH for which PDCCH provides control information is transmitted is required. A field including such a carrier indicator is hereinafter called a carrier indication field (CIF).

A multi-carrier system supporting cross carrier scheduling may include a carrier indication field (CIF) in a conventional downlink control information (DCI) format. In the system supporting cross-carrier scheduling, for example, in the LTE-A system, since CIF is added to the existing DCI format (that is, the DCI format used in LTE), 1 to 3 bits can be extended, and the PDCCH structure is conventionally coded. Method, resource allocation method (ie, CCE-based resource mapping) can be reused.

In addition, in a multi-carrier system, the number of component carriers aggregated between downlink and uplink may be set differently. The case where the number of downlink CCs and the number of uplink CCs are the same is called symmetric aggregation, and when the number is different, it is called asymmetric aggregation.

9 illustrates asymmetric aggregation with three serving cells configured for the UE.

9, PCell, SCell 1, and SCell 2 are configured in a terminal. In PCell, DL PCC and UL PCC are linked by SIB 2. In SCell 1, DL SCC 1 and UL SCC 1 are linked by SIB 2. In contrast, SCell 2 has only DL SCC 2.

FIG. 10 illustrates an example of an SRS triggering method in the situation of FIG. 9.

Referring to FIG. 10, the base station transmits the PDCCH through the DL PCC of the PCell. This PDCCH may include an SRS triggering signal while scheduling a PDSCH of subframe N transmitted in DL SCC 1 of SCell 1. When cross carrier scheduling is performed as described above, according to the related art, the UE transmits SRS through DL SCC 1 of SCell 1 receiving the PDSCH through subframe M of UL SCC 1 linked by SIB 2. It is prescribed to transmit.

SIB 2 is one of system information types. System information is configured through a system information block (SIB), where each system information block includes a set of parameters related to a function. The system information block is divided into various types as follows.

1. Master information block (MIB): The MIB contains essential parameters related to the initial access of the terminal to the network, which are the limited number of parameters that are transmitted most often. The MIB may be transmitted through a physical broadcast channel (PBCH).

2. SIB 1: SIB 1 includes information about time domain scheduling of other SIBs and parameters related to cell selection.

3. SIB 2: SIB 2 includes common channel information. For example, SIB 2 may include information indicating a link relationship between an uplink component carrier and a downlink component carrier.

In addition to the above-described system information block, there are SIB 3 to SIB 8. SIBs may be transmitted on the PDSCH.

That is, according to the related art, SRS is transmitted through a downlink component carrier receiving the PDSCH and an uplink component carrier linked by SIB 2.

As shown in the example of FIG. 10, when each serving cell includes DL CCs and UL CCs in pairs, SRS transmission may not be a problem even by the prior art.

FIG. 11 illustrates a case where SRS transmission is a problem in the situation of FIG. 9.

Referring to FIG. 11, the PCell is composed of DL PCC and UL PCC, but SCell 2 is composed of DL SCC 2 only. In this case, the base station may transmit the PDCCH in subframe N of the DL PCC of the PCell. At this time, the PDCCH may include the SRS triggering signal while scheduling DL SCC 2 of SCell 2. At this time, there may be no UL CC linked to DL SCC 2 and SIB 2 of SCell 2 receiving the PDSCH. Therefore, it is a matter of which UE should transmit the SRS through the UL CC of which serving cell.

This problem is not limited to multi-carrier systems. For example, the same problem may occur in a cooperative multi-point transmission / reception (CoMP).

First we define the term for CoMP.

Hereinafter, a CA set refers to a set of cells aggregated by a terminal. CA cell means a cell belonging to a CA set.

A primary cell (PCell) refers to one cell among cells belonging to a CA set as described above, and has the following properties. That is, it means a cell having an RRC connection with the base station among the cells in which the terminal is aggregated. The terminal obtains main system information such as PBCH, PDCCH in common search space, etc. through DL CC of PCell. Further, the PUCCH carrying ACK / NACK, CSI, etc. may be transmitted through an uplink component carrier of the PCell. In other words, a cell having the above-described characteristics is called a PCell.

SCell refers to cells that are not PCell among the cells aggregated by the terminal.

The CoMP set refers to cells to which a CoMP operation is applied among cells aggregated by a terminal. Herein, a cell to which a CoMP operation is applied includes a joint transmission (JT) in which a plurality of base stations cooperate to simultaneously transmit a signal, coordinated scheduling (CS) in which one base station transmits a signal by scheduling among a plurality of cooperative base stations, A cell participating in various CoMP operations such as dynamic cell selection, coordinated beam forming (CB) in which a plurality of base stations cooperate to perform beamforming, or a cell which is a candidate to participate in.

CoMP cell means a cell included in a CoMP set.

Among CoMP cells, CoMP PCell means a cell having the following characteristics among cells belonging to a CoMP set. That is, CoMP PCell is a cell that transmits PDCCH scheduling PDSCH / PUSCH transmission for CoMP cells belonging to the CoMP set when cross-carrier scheduling is applied in the CoMP set. Such CoMP PCell may be configured in the same manner as the PCell described above, or may be configured separately from the PCell through RRC signaling.

CoMP SCell means a cell that is not a CoMP PCell among the cells belonging to the CoMP set.

In the above definition, the component carrier included in the SCell or CoMP SCell may be a new type of carrier file different from the previously defined carrier. That is, the existing carriers follow the conventional standard so that the UE can directly access them directly. For example, the existing carrier assumes that PBCH, synchronization channel, common reference signal (CRS), and common control channels through which system information is transmitted exist according to the existing standard. However, in the present invention, the component carrier used for the SCell and CoMP SCell is not necessarily limited to the same carrier as the existing carrier. That is, the existing terminal may not be recognized because there is no synchronization channel, CRS, etc., but a new type of carrier fire that an advanced UE may recognize may be used. This is because, when the SCell is used by carrier aggregation while the RRC connection is already established, the PBCH and the synchronization channel may be unnecessary channels, which may limit the efficient use of frequency resources.

12 shows a CoMP system to which the present invention can be applied. In FIG. 12, a cell used by a serving base station and a cell used by a cooperative base station may be a CoMP set, a cell used by a serving base station may be a CoMP PCell, and a cell used by a cooperative base station may be a CoMP SCell.

Referring to FIG. 12, UE 1 is present in coverage in a serving eNB and also in coverage of a coordinating eNB. That is, the terminal 1 may exist outside the coverage of the serving base station. The carrier used by the serving base station and the carrier used by the cooperative base station may have the same frequency band or may have different frequency bands. The carrier used by each base station can be identified by a carrier indication field (CIF).

UE 1 may receive a PDCCH from a serving base station, and may selectively or simultaneously receive a PDSCH scheduled by the PDCCH from a serving base station or a cooperating base station. In this case, when the SRS triggering signal is present in the PDCCH, it may be a problem for which UL CC the UE 1 should transmit the SRS.


As described above, in the carrier aggregation situation, when there is no UL CC linked to SIB 2 in the DL CC to which the PDSCH scheduled through the PDCCH is transmitted, or for the DL CC in which the PDSCH is transmitted to some CoMP cells in the CoMP situation Even if there is a UL CC linked to SIB 2, there is a problem when uplink transmission is not configured in a subframe in which SRS should be transmitted.

In order to solve this problem, in the present invention, the UL CC to transmit the aperiodic SRS may be predetermined to a specific UL CC (or a specific UL CC group). For example, the specific UL CC may be a CC configured to allow the UE to receive system information or transmit PUCCH. That is, it may be determined in advance that the SRS is always transmitted through the UL PCC of the PCell.

13 shows an SRS transmission method of a terminal according to an embodiment of the present invention.

Referring to FIG. 13, it is assumed that base station #N uses DL CC # 1 and UL CC # 1, and base station #M uses DL CC # 2 and UL CC # 2. At this time, the base station #N and the base station #M are base stations that perform CoMP operation.

The base station #N may trigger the SRS through PDCCH # 1 scheduling the PDSCH of the DL CC # 2 (S110). In this case, PDCCH # 1 may be transmitted through DL CC # 1.

The base station #M transmits the PDSCH through the DL CC # 2 (S120).

The terminal transmits the SRS through a predetermined UL CC # 1 (S130). In this case, DL CC # 1 may be DL PCC, and UL CC # 1 may be UL PCC.


Or, even when there is no UL CC linked to SIB 2 or a UL CC linked to SIB 2 in a DL CC to which a PDSCH scheduled through PDCCH is transmitted, uplink transmission is not configured in a subframe in which SRS should be transmitted. In this case, the UL CC to transmit the aperiodic SRS triggered by the corresponding PDCCH may use a UL CC or a UL CC set indicated through UE-specific RRC signaling. This method has an overhead due to RRC signaling but has the advantage of being flexible.

14 shows an SRS transmission method of a terminal according to another embodiment of the present invention. In this case, it is assumed that the UE is a case in which serving cell # 1 composed of DL CC # 1 and UL CC # 1 and serving cell # 2 composed only of DL CC # 2 are configured.

Referring to FIG. 14, the base station indicates a carrier to transmit SRS in an RRC signal (S210). The RRC signal may be transmitted through DL CC # 1. The RRC signal may include not only a carrier for transmitting the SRS but also time information for transmitting the SRS through the carrier. That is, the SRS may be transmitted through the carrier only during the time interval specified by the time information. Information and time information indicating a carrier to transmit the SRS included in the RRC signal may have a UE-specific value.

The base station may trigger the SRS through the PDCCH scheduling the PDSCH of the DL CC # 2 (S220). The PDCCH may be transmitted through DL CC # 1.

The terminal transmits the SRS through the UL CC set to the RRC signal (S230). For example, if the carrier to transmit the SRS in the RRC signal is indicated by the UL CC # 1, the UE receives the PDSCH through DL CC # 2, but the SRS may be transmitted through the UL CC # 1. Therefore, even though there is no UL CC linked to DL CC # 2, the UE can transmit the SRS. In addition, even if there is a UL CC linked to DL CC # 2, but there is no uplink transmission in a subframe in which the SRS is transmitted, the UE may transmit the SRS.

In addition to the above-described method, the following method may be applied to transmit the SRS.

If there is no UL CC linked to SIB 2 in the DL CC receiving the PDSCH scheduled through the PDCCH, or if there is no UL CC linked to SIB 2, uplink transmission is not configured in the corresponding subframe, the entire UE is configured The SRS may be transmitted through the UL CC. If the activation / deactivation state is different for each UL CC, the SRS may be transmitted using only the activated UL CC.

Or, in the case of cross-carrier scheduling, aperiodic SRS may be transmitted through a DL CC transmitting a PDCCH including an SRS triggering signal and a UL CC linked to SIB 2. For example, in the example of FIG. 9, in case of cross-carrier scheduling, the DL PCC may be set to a DL CC on which a PDCCH is transmitted. In this case, since the UL PCC linked to SIB 2 always exists in the DL PCC, SRS may be transmitted through the UL PCC.

In the case of non-cross carrier scheduling, the PDCCH is transmitted through DL SCC 2 of SCell 2, and at this time, there is no UL CC linked to SIB 2 in DL SCC 2. Accordingly, the PDCCH transmitted in the DL SCC 2 may not include a signal for triggering an aperiodic SRS or may be determined that the UE does not transmit the SRS even if it includes the signal.

Alternatively, the PDCCH for scheduling the PDSCH transmitted to the DL CC without the UL CC linked to the SIB 2 may not include a signal for triggering the aperiodic SRS even if used for cross-carrier scheduling. Alternatively, even if the PDCCH includes a signal for triggering aperiodic SRS, the UE may ignore the SRS without transmitting the SRS.

Through the above-described method, the UE is uplinked in a subframe in which SRS should be transmitted even if there is no UL CC linked to SIB 2 or a UL CC linked to SIB 2 in the DL CC through which the PDSCH scheduled through the PDCCH is transmitted. SRS may be transmitted even when link transmission is not established. The base station can estimate the uplink channel quality by measuring the SRS, and can perform scheduling using the result. The result is an increase in system performance and efficiency.

15 is a block diagram illustrating a base station and a terminal.

The base station 100 includes a processor 110, a memory 120, and an RF unit 130. The processor 110 implements the proposed functions, processes and / or methods. For example, the processor 110 may indicate a carrier to which the terminal will transmit the SRS through the RRC signal, and may transmit time information to which the carrier is applied. In addition, the processor 110 may measure uplink channel quality and perform scheduling by measuring the SRS transmitted by the terminal. The memory 120 is connected to the processor 110 and stores various information for driving the processor 110. The RF unit 130 is connected to the processor 110 and transmits and / or receives a radio signal.

The terminal 200 includes a processor 210, a memory 220, and an RF unit 230. The processor 210 performs the functions, processes, and methods described above. For example, the processor 210 may receive carrier information and time information for transmitting the SRS through the RRC signal and transmit the SRS through the corresponding carrier. In some cases, the SRS triggering signal included in the PDCCH may be ignored and the SRS may not be transmitted. Layers of the air interface protocol may be implemented by the processor 210. The memory 220 is connected to the processor 210 and stores various information for driving the processor 210. The RF unit 230 is connected to the processor 210 to transmit and / or receive a radio signal.

Processors 110 and 210 may include application-specific integrated circuits (ASICs), other chipsets, logic circuits, data processing devices, and / or converters for interconverting baseband signals and wireless signals. The OFDM transmitter and OFDM receiver of FIG. 7 may be implemented within processors 110 and 210. The memory 120, 220 may include read-only memory (ROM), random access memory (RAM), flash memory, memory card, storage medium, and / or other storage device. The RF unit 130 and 230 may include one or more antennas for transmitting and / or receiving a radio signal. When the embodiment is implemented in software, the above-described technique may be implemented as a module (process, function, etc.) for performing the above-described function. The module may be stored in the memories 120 and 220 and executed by the processors 110 and 210. The memories 120 and 220 may be inside or outside the processors 110 and 210, and may be connected to the processors 110 and 210 by various well-known means.

Although the present invention has been described above with reference to the embodiments, it will be apparent to those skilled in the art that the present invention may be modified and changed in various ways without departing from the spirit and scope of the present invention. I can understand. Therefore, the present invention is not limited to the above-described embodiment, and the present invention will include all embodiments within the scope of the following claims.

Claims (14)

  1. In the sounding reference signal transmission method of the terminal,
    Receiving carrier information indicating a carrier to transmit a sounding reference signal;
    Receiving a physical downlink shared channel (PDSCH) on a first downlink component carrier; And
    Transmitting a sounding reference signal through a second uplink component carrier,
    The second uplink component carrier is determined based on the carrier information.
  2. The method of claim 1, wherein the first downlink component carrier is a downlink component carrier without an uplink component carrier linked by system information.
  3. The method of claim 1, wherein the first downlink component carrier is a downlink component carrier link linked with the first uplink component carrier by the system information,
    The first uplink component carrier is characterized in that uplink transmission is not configured in a subframe transmitting the sounding reference signal.
  4. The method of claim 1, further comprising receiving a physical downlink control channel (PDCCH) for scheduling the PDSCH from a serving base station.
    The PDSCH is received from a cooperating base station cooperatively transmitting with the serving base station, and the sounding reference signal is transmitted to the serving base station.
  5. 5. The method of claim 4, wherein the PDCCH comprises a signal that triggers the sounding reference signal transmission.
  6. The method of claim 1, wherein the carrier information is received through a radio resource control (RRC) signal.
  7. In the sounding reference signal transmission method of the terminal,
    Receiving a physical downlink shared channel (PDSCH) on a first downlink component carrier; And
    Transmitting a sounding reference signal through a second uplink component carrier,
    And the second uplink component carrier is a predetermined uplink component carrier.
  8. 8. The method of claim 7, wherein the second uplink component carrier is an uplink component carrier included in a primary cell in which the terminal performs an initial connection establishment procedure or connection reestablishment procedure with a base station. How to.
  9. RF unit for transmitting and receiving a radio signal; And
    A processor connected to the RF unit, wherein the processor
    Receiving carrier information indicating a carrier to transmit a sounding reference signal, receiving a physical downlink shared channel (PDSCH) through a first downlink component carrier, and transmitting a sounding reference signal through a second uplink component carrier Including steps,
    The second uplink component carrier is characterized in that determined based on the carrier information.
  10. The terminal of claim 9, wherein the first downlink component carrier is a downlink component carrier without an uplink component carrier linked by system information.
  11. 10. The method of claim 9, wherein the first downlink component carrier is a downlink component carrier link linked with the first uplink component carrier by the system information,
    The first uplink component carrier is a terminal characterized in that uplink transmission is not configured in a subframe transmitting the sounding reference signal.
  12. 10. The method of claim 9, wherein the processor further receives a physical downlink control channel (PDCCH) for scheduling the PDSCH from a serving base station,
    The PDSCH is received from a cooperating base station cooperatively transmitting with the serving base station, and the sounding reference signal is characterized in that for transmitting to the serving base station.
  13. The terminal of claim 12, wherein the PDCCH includes a signal for triggering the sounding reference signal transmission.
  14. The terminal of claim 9, wherein the carrier information is received through a radio resource control (RRC) signal.
PCT/KR2012/001573 2011-03-02 2012-03-02 Method and apparatus for transmitting a sounding reference signal by a terminal WO2012118343A2 (en)

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